I’ve been an investor and board member in/of comScore since 1999 and am clearly biased, but I also know a lot about this stuff. I left comScore’s board in June (a bittersweet moment) but I still own a lot of comScore stock through our Flatiron partnerships. So consider me an interested and biased party to this discussion.

Nevertheless, I still think that Google has a lot of work to do to get their data right. comScore’s been at this stuff for ten years. The team who started and run the business has been in the market data business for close to thirty years. And they are hard core stastics people who understand panels and how to project using statistically significant and unbiased data.

So far, [Google is] not so good on this measure. As Gian and Comscore have long
pointed out to me, it takes more than raw data to make for good
measurement. Ideally, you weight your data with a lot more knowledge of
its context – what kind of machine is creating it (work or home? Man or
woman? etc.). While Google once blended Comscore demographic data into
its ad network, Comscore confirmed to me that this is no longer the
case. And while it is subject to endless criticism, Comscore does have
a lot more practice at this game than does Google. At least for now.

If you care about this stuff, go read John’s post. There are several charts in it that make the point clearly.